Feels like copy paste from chinese into english in google t ranslator. Instructions that came with the product are really really bad translated. That will make charges on your sim in the sensor alarm. This model sends you back sms when you turn it on, off or change settings. If you place sensor beside a wall, into a tube or under a chair, so that the sensor does not have enough width (more then let's say 90 degrees) then the sensor does not work! I tested the sensor range which is correct. If you insert multiple numbers the device calls each separately one after another, not all at once. Hot WiFi Mini PIR Motion Sensor Infrared Alarm Detector For Tuya Smart Life APP. The detector has the following features: x Detection distance up to 15 meters (49.2 ft. After movement the device calls you in 10-15 seconds. The security alarm starter kit includes: the hub U-Prox MP or U-Prox MP WiFi the brain of the system, which interacts with all devices U-Prox PIR infrared motion detector with 3 sensitivity levels U-Prox WDC magnetic contact detector U-Prox Keypad G1 or U-Prox Keyfob, depending on the kit. The MP -841 pet immune detector is a microprocessor -controlled wireless digital PIR detector supported by ZigBee H ome A utomation 1.2.